Rail fastening



NOV. 28, W. KAEMPF 1,936,965

RAIL FASTENING Filed Nov. 30, 1931 Patented Nov. 28, 1933 -Germanyffxw l AA/pplica'tion ANovember 361] Iniet, serialiA Naf 4comms. lomas-aon v My invention relateslto improvements e in rail fastenings, and. more particularly in a rail fas-V tening comprising tiefpl'ates andA wedges for fixing the rail thereto. In constructions of this type a wedge is driven into position on one orfboth i sidesof the. railbetween lone or bothflanges of.

1 the rails and prongs tie-plate. p U 1 l ,e y The fastening of the rail by means of wedges is or catches provided on the f u reliable and simple, rand it results in a strong fas-y tening. However, notwithstanding the great advantages ofthe construction, the'fastening of the rails based` on the use of wedges hasnot come into general use, the reason being that the practical and theoretical conditions `'of ,thesaid fastening have not been generally understood.

In fastenings of the type referred to, which are subject tocontinuousfvibrations,it is important that the wedges and the members engaging the same make contactwith their whole surfaces; and that they bear'on each other not only withaa few points or with two lines constructions heretofore proposed this-prerequisite has not inany wa-yf'been` taken intoconsideration. `Thus it; has

been suggested,: for exampleftodrive the wedge between two parallel surfaces; ,Iherefore the wedge was atA one side onlyl in. linear'v contact, which contact wasgin some cases confined to avery narrow surface byv deformation of the mate'- w rial. A further deficiency of allthe constructionsv heretofore in use was that in -no way wasjcare taken Ito compensate objectionable clearances which' necessarily result fromthefinacuracies' of' theparts manufactured on'a large scale when assembling thesame, so thatbodieswhichztheoretically should be in full surface contact; and ther drawing of whichshowedsuch surface contact, practically made contact only-"along a line or with a few points. Y

The prongs or catches formed on the tie-plates areV made exceedingly strong. and' solid. and frequently they are reinforced by ribs thus providi ing a rigid and completely non-elastic body,k which results in anexce'ssive strain of the saidparts and high surface pressure and rapid and non-- uniform wear of the engagingfelements. Thereby thel fasteningpis rapidly made loose, which results in an enlargement of the gauge and other objections the repair of which requiresexpensive' V and difficult Work.

Further, all those fastenings comprising Wedges are objectionable in which the wedges are held in position by hooks which are Vfixed in holes made in the tie. By'the Vibration caused by the cars i cracks are produced in the ties beginning from are preferably constructed as beams the said'holes. `By such destruction of the material; 'astrong jointV is made impossible, and the Wedges f are rapidly `made loose. The'.`A life of (the tiesa is: materially reduced, Va-ndthe costtof -the super-structure 'is increased. `Also whenusng wooden-wedgesrthere-fis the danger; of the; structurelbecomingfloose, even if betweenthe foot of the prong and the edge of the: base flangeof the -Byfproviding a large number of elementsthe number of -the possible clearances which interfereWith, a; strong joint is increased; i

TheV object of the improvements Vvisy to provide yraila ttingfpie'ce is inserted, andthe wooden f ,Y I

a fastening in which the aforesaid objectionsare i olviateclf l In `my irmzvroved construction I make use of 'normal tie'shaving `no holes,` Vimpressions orbulgle'd portionsfor the prongsror catches.` The irontieeplates'are'welded to the-ties or-secured to Woodenffties'," They-jara providedl each with two prongs'or'catches onwhich the wedges are sup.-` ported with their4v whole bearing. surfaces; the inner surfacesf'of the prongs or catches and` the corresponding faces ofthe wedgeshavingcorre-A spondingiinclination Aand shape when the wedge i has been driven onto the tiefplate,so that`v the said. parts have large bearing surfaces. The prongs ,or catches areconstructed so thaththey compensate for the difference inshapereSulting fromA the unavoidablevclearances and that the wedge ,and the prongs Aare incomplete contact at Atheir bearingY faces. Such close engagementjofthe. elements notwithstanding the difference in the dimensions is possible only if the prongs. are

able, by theiry elasticity andl special shape, completely to adapt themselvesl to the shape of the Wedge- 4V; l

f Therefore the prong 'is made elastic,l and pref-` era-bly it takes the' form of -a bodyin which the bending stress is alike throughout ,thelength' of the prong, and whichiscapableofbeingbentfto a large degree, and whichvfinallyi'is adapted to Iliff take up the longitudinal: 'and transverse forces. f

yThe degree of the necessaryl deformation by bend' satedfor, and the material' of 'the tie-plate is seLv` mit a maximum bending deformation, the prongs f resistanceragainst bending.

l VIn addition to the `said features relating to struco of uniform lplate the contacting surface of the A2vir vture'and material, also the shape of the prong relatively to the wedge is important.

Before the Wedge has been driven on to the tie- Wedge and the prong have dilferent curvatures. When the wedge is loosely set into the cavity of the prong or catch, the upper edge of the said prong or catch makes contact with the curved top part of the Wedge along a line, because the prong and the wedge have equal pitch. By driving in the wedge the prong is bent outwardly at its top end, and.r the line contact is gradually changed to a surface .y

contact. Thus the Wedge is gradually driven' into position while the prong is elastically bent` outlarge lateral binding forces for thebase of the rail..

Afterrthe wedge -has been drivenin' and the joint has been made, the prong isunder tension,

' while it is relieved of pressure when the wedge and the fastening are loose.

f- In order that my invention be more clearly unl 305l derstood an exampleembodying the same has been shown Ain the accompanying-drawing in which. the lsame reference charactershave been used in 'all the views 4to indicate' corresponding.

parts. In said drawing, r f v l Fig. 1 is a sectional elevation showing the `rail Y Fig. 2 is` a .top plan view of Fig. 1, y

f Figsgto 5 are detail sectional elevations show?.

ingthe wedge inposition, Fig. Sshowing the wedge loose, Fig. 4 showing the same partly driven in,

and Fig. 5 showing the same in final position, and Fig.v 6 is ar diagrammatical viewv showing the curvature of the prong and the deformation v thereof. 45"l As is'shown in Figs. 1 and 2, thefasteningV coinprises a rail a, a tie-plate b adapted to be secured vto the'tie, and formed with a pair'of prongs or catchesc, and wedges d engaging theprongs and thebase flange of the rail. y k As is best shown in Figs. 3 to 5, the prongs are formed with an inner curved face c1, andr theV wedge d is formed with a corresponding curved face d1 and withra longitudinal notch d2l engaging the edgeof the `base flange of the rail. While the wedge d is in loose engagement with the prong Yc' the radii of the curvature of the faces c1 and d1 are different, the radius of the curvature of thefface c1 beingr smaller than that of the face d1. But when the wedge has been driven on into the nal position shown in Fig.` 5, the prong is deformed Yso far thatv the said curvatures arealike and thefaces c1 and d1 are in full contact.V

' In Fig. 6 I have'illustrated theshapeand position ofthe prong, and more particularly of the of the lface c1 while the Wedge is loose and the' prong is not lunder tension, and the full line lof its elasticity it 'will Yfollow pa'rtsand with the whole-.surfaces c1 and d1.

t 5 'The angle of the wedgemust be much smaller than the angle of friction ofthe iron. The said angleY of friction is 12 30', and therefore the angIeofthe'Wedge should be only one eleventh or 'one twelfth'of the said angle,Y so that the 1 pitch of th wedge is about,2,5%. I Figs. 3 to show the position and, shape of the prong and wedge in the differentv positions :of thewedge, Fig. 3 showing thewedge loosely fitted between the lprong and the base flange, Fig. lk

showing the vsame partly .driven in, andFig. 5 showing the same-in nal position. l A

' The prcngis gradually reduced in cross-section from itsV base towards 'its Outeren'd, the said reduction being such rthat the bendingstress is the same in allparts ofthe height of theprong. Further, the radius of the curvature of the surface., clof the prong is so much smaller than lthatl of the surface dlo'f the Awedge that 'after' bending to compensate for vthe allowance, 'and after the wedgehas beenvforced into'nal position,-the prong'and the wedge'. are in close con- 110 tact with each other.

ljIn farrail fastening, the combination with a tieA plate having ian integrallyformed upstanding.' elastic prong having -an 'inner facev l'adapted 115 to extend generally in the direction ofthe 4rail flange, saidface curving 'upwardly and inwardly toward therail', of'a Wedge member coacting a tie plate having anlintegrally formed upstand ing elasticprong having an' inner face' adapted to extend generally in the direction ofthe rail flange, "said face curvingnpwardly and inwardly toward therail, oi a wedge member coacting with the rail flange and thev prongandhaving a `face corresponding torand of initially greater radius of curvature than the face vof the prong,v the'r'atioof the radiil of curvature of the'coo'perating' faces 'ofthe wedge member and prong being such'that the deformation of the prong vvon the driving of thexwedge''rnembe'r into position rensures contact of the said cooperating faces'o'ver 140 a imajclxr portionthereof.

i WALTERfKnEMPF;

Y g v125 2.*In`a rail fastening, the combination-With 

